Easy-open can ends are well known in the field of can manufacture—for example, that disclosed in FIGS. 4 & 5 of U.S. Pat. No. 5,413,241 (YEH HSI-SHOU) 9 May 1995. The can end disclosed is provided with an end panel having a score line defining a prearranged opening area to provide a “full-aperture” end. By “full aperture” is meant having the prearranged opening area covering virtually all of the area of the end panel. A tab is secured to the end panel, with the nose of the tab located adjacent the score line. To avoid interference between adjacent can ends during their transportation, the handle of the tab is located tight against the outer surface of the end panel. It would remain in this position after attachment of the can end to a can body—as is normal practice for virtually all current easy-open can ends. However, this presents a problem for a consumer wishing to open the can because they must first prise the handle of the tab away from the surface of the end panel in order to lift the tab to rupture the score line. The lack of clearance between the tab handle and the end panel makes this a difficult task, especially for those with weak hands.
U.S. Pat. No. 7,168,586 B (CROWN PACKAGING TECHNOLOGY, INC) 30 Jan. 2007 provides one solution to the above problem of tab access. U.S. Pat. No. 7,168,586B2 discloses a “full-aperture” easy-open can end with a score line defining a prearranged opening area. The can end disclosed has a collapsible protrusion under the handle of the tab, the collapsible protrusion deformable between two states. Initially, the collapsible protrusion protrudes upward from the can end to define a minimal (or zero) gap between the handle of the tab and the protrusion. This provides efficient stackability of one can end upon another for storage/transportation purposes and avoids adjacent can ends becoming caught between the handle of the tab and the can end. The protrusion is deformable downwards from the tab into a second state, to define a concave finger well under the handle of the tab sufficient for a user to insert their finger.
However, there are several problems with the protrusion shown and described in U.S. Pat. No. 7,168,586B2:                The invention of U.S. Pat. No. 7,168,586B2 is not suitable for large diameter “full-aperture” can ends. For the purpose of this application, large diameter means larger than about 4 inches). The reason for this is that to preserve easy stackability without having to index each can end relative to another, the protrusion must be centrally located on the can end. However, for full-aperture can ends, the tab must be situated near the periphery of the can end in order for the nose of the tab to be adjacent the score line for opening. These two requirements increasingly conflict with each other for larger diameter can ends. Consequently, as can end diameter increases, a far deeper protrusion is required to provide a given amount of finger access under the handle of the tab. Ultimately, it becomes impossible to form a sufficiently deep protrusion under the tab to enable finger access.        The collapsible protrusion of U.S. Pat. No. 7,168,586B2 has to occupy a substantial area of the can end to define a finger well of sufficient depth to permit a consumer to insert their finger under the tab.        Further, providing an increase in tab access when using such a finger well under the handle of the tab typically necessitates either or both of:         i. using a finger well which occupies a greater area of the can end; or         ii. a greater amount of stretching of the metal to form the collapsible protrusion.        Additionally, the protrusion of U.S. Pat. No. 7,168,586B2 is a non-planar surface, which can present a difficult surface on which to print logos, images or instructions.        
There is therefore a need for an improved can end, which can be transformed from first to second states to provide improved tab access.